1. Technical Field
The present invention relates to a receiving apparatus which receives a broadcast signal from a broadcasting-station apparatus, and a display apparatus and a television broadcasting system in which this receiving apparatus is used. It relates to, for example, a receiving apparatus which receives a broadcast signal from a head-end apparatus of a CATV (or cable television) station, and a display apparatus and a CATV system in which this receiving apparatus is used.
2. Background Art
In the United States, a CATV system has become popular which can broadcast through a large number of channels. Also, a digital broadcasting method has enabled high-definition broadcasting using a lot of channels. As such a CATV system, for example, Japanese patent application Laid-Open No. 2002-308030 discloses the following CATV system. In order to realize power savings in terminal equipment such as a receiving apparatus, there are provided a head end which transmits downstream data, and terminal equipment which receives downstream data that is transmitted from the head end. The terminal includes a tuner, a demodulation circuit, a CPU (or central processing unit) and a switch circuit. The CPU turns on the switch circuit at a predetermined time to turn on the power of the tuner and the demodulation circuit.
However, in this terminal, the CPU needs to turn the switch circuit on and off. Even in a sleep mode where no cable broadcast is supposed to be received, the CPU's power is required to be turned on. Hence, in the terminal equipment power consumption cannot be reduced enough during sleep mode.
In addition, when the terminal equipment is in a power-on mode, or when its power is turned on, downstream data for turning on or off the switch circuit needs to be transmitted from the head end. Thus, such downstream data for turning on or off the switch circuit cannot be transmitted at an arbitrary time.